Original post found here....
The beautiful bass you just took off a 35-foot rockpile is floating belly-up. Now what? You know the problem. Its distended gut tells you the swim bladder is expanded, which keeps the fish from diving to bottom. You also know the solution—fizzing. But frankly, jamming a hollow, 18-gauge needle into a fish's vitals isn't exactly in your comfort zone.
Watch this 7-minute video, produced by Texas Wildlife & Parks fisheries biologists, though, and the mystery will dissolve like lake mist under a rising sun. The term for this condition is: barotrauma, and it happens when bladder gas expands as a fish is reeled from deep water to the surface. Reversing the condition is easy, if you know the steps, and it's a skill every angler should master.
As a bonus, there's a section that'll take you back to your high school biology room's dissection table. But if you're squeamish, you can close your eyes for that part.